1. Field of the Invention
This invention relates to a power source apparatus of portable computer such as a notebook type personal computer, a word processor, and so forth. More specifically, this invention relates to an apparatus for supplying electric power from a portable computer to an extended station when the extended station is provided to the portable computer.
The present invention relates also to an apparatus for supplying electric power from a portable computer to an extended station when the portable computer has an add-on battery and/or an AC adaptor that can be connected to the portable computer.
2. Description of the Related Art
Recently, portable computers constructed to have a small size and a light weight have become widespread in consideration of portability, such as notebook-type personal computers and wordprocessors, and extended stations for portable computers, for extending various functions of the portable computers, are fitted mechanically and electrically to the portable computers.
When a portable computer and an extended station are connected, their weak electric circuits are connected with each other through connectors. Therefore, the weak electric circuits must be protected from an excessive load or damage due to short-circuit that may occur if the connectors are fitted incorrectly, e.g. obliquely, and so forth.
In general, batteries have life characteristics such that, if the power consumption per battery cell is great, battery life becomes short. Therefore, power consumption per cell must be limited.
In conventional type portable computers and extended stations according to the prior art, it has been necessary to stop the system when the portable computer and the extended station are connected, and to turn off a power source, so as to prevent damage to the weak electric circuits, and to activate the system again by turning on the power source.
A battery mounted on a conventional portable computer supplies power from the same number of cells even when power consumption changes due to the extended station, etc.
Japanese Unexamined Patent Publication (Kokai) No. 8-76879, for example, describes the use of a peripheral device while it is superposed with, and below, the portable computer.
Japanese Unexamined Patent Publication (Kokai) No. 8-76889, on the other hand, discloses a connection structure between an information processing apparatus and a peripheral apparatus, wherein a pair of connector shell portions for the connection with a computer are formed on the housing of an extended unit connected to the information processing apparatus, these shell portions and the housing on which the shell portions are formed are integrally molded from a resin material, and metallic plating is applied to the entire surface.
Japanese Examined Patent Publication (Kokoku) No. 8-7651 discloses that, in a portable computer of a type which is put on a docking apparatus for a portable computer and which has a signal transmission electric connection portion for transmission with the docking apparatus, a portable computer, including a contact portion which is disposed on the main body of the portable computer, is connected to a reference potential portion of the computer main body and is brought into contact with a portion to be connected to the reference potential portion of the main body of the docking apparatus at a position spaced apart from the signal transmission electric connection portion, in order to reduce an electromagnetic wave noise resulting from the potential difference between the portable computer and its docking apparatus.
As described above, the prior art technologies involve the problem in that the coupling operation is time consuming at the time of coupling of the portable computer and its extended station, because the system must be first stopped by turning off the power source and must be again activated by turning on the power source after coupling is completed.
The prior art technologies involve another problem in that, if the power consumption quantity per cell of the battery becomes great due to fitting of the extended station, the battery life is shortened.